To assess the effect of oral propranolol and oral verapamil on left ventricular systolic function and left ventricular diastolic filling in patients with coronary artery disease, we analyzed high temporal resolution time activity curves from radionuclide cineangiography at rest in 11 patients before and during therapy with each of these medications. Left ventricular ejection fraction was normal at rest in 8 of 11 patients, but diastolic filling was abnormal in all 11. Propranolol did not alter ejection fraction or diastolic filling. In contrast, verapamil significantly reduced ejection fraction, yet significantly improved diastolic filling, by increasing peak left ventricular filling rate and by reducing the time to peak filling rate. The improvement in diastolic filling, despite decreased ejection fraction, may account in part for the symptomatic improvement observed in many patients during verapamil therapy.